A 15-year-old boy has a 4-month history of progressive shortness of breath with exertion, muscle weakness, and worsening exercise tolerance. Vitals are within normal limits. Physical examination shows bilateral ptosis. Muscle strength is 3/5 in all extremities. A pedigree is shown. The patient is represented by III-10.
Which of the following combinations of findings is most likely in this patient?
↑ Serum lactate; ↑ Max O2 consumption; ↑ Glycolytic energy production
↑ Serum lactate; ↑ Max O2 consumption; ↓ Glycolytic energy production
↑ Serum lactate; ↓ Max O2 consumption; ↑ Glycolytic energy production
↑ Serum lactate; ↓ Max O2 consumption; ↓ Glycolytic energy production
↓ Serum lactate; ↑ Max O2 consumption; ↑ Glycolytic energy production
↓ Serum lactate; ↑ Max O2 consumption; ↓ Glycolytic energy production
↓ Serum lactate; ↓ Max O2 consumption; ↑ Glycolytic energy production
↓ Serum lactate; ↓ Max O2 consumption; ↓ Glycolytic energy production
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Cut-to-the-chase Answer (0:55):
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HY USMLE Answer (5:18):
